As electronic apparatuses, such as a mobile telephone and a personal computer, have had advanced functions and a small size, an input device used in these apparatuses is demanded to operate reliably in various ways.
FIG. 14 is a cross sectional view of conventional input device 501. Actuator 1 having a spherical shape is made of insulating resin. Plural magnets 2 made of ferrite and having substantially a disk shape are embedded in an outer circumference surface of actuator 1. Upper case 3 and lower case 4 are made of a thin metal plate. Operation unit 1 having the spherical shape is accommodated rotatably between upper case 3 and lower case 4. An upper portion part of actuator 1 protrudes from an opening formed in an upper surface of upper case 3. Plural wiring patterns are formed on upper and lower surfaces of a circuit board. Four magnetic sensors 6, such as Hall elements, are mounted on the upper surface of circuit board 5 in front, rear, left and right directions facing actuator 1 with a predetermined gap. Controller 7, such as a microcomputer, is also mounted onto the upper surface of circuit board 5. Four magnetic sensors 6 are connected to controller 7 via the wiring patterns, thus constituting input device 501.
Input device 501 is installed in an operating panel of an electronic apparatus, such as a mobile telephone or a personal computer, while the upper portion of actuator 1 protrudes. Controller 7 is electrically connected to an electronic circuit of the electronic apparatus via a connector and a lead wire.
While plural menus, such as a name and a title of music or a cursor are displayed on a display, such as a liquid crystal display element of the electronic apparatus, when an operator rotates an upper portion of actuator 1 with a finger forward, backward, leftward or rightward, magnets 2 embedded in the outer circumference of actuator 1 moves along the circumference of actuator 1. If actuator 1 rotates leftward, magnet 2A first approaches magnetic sensor 6, and then, magnet 2B approaches magnetic sensor 6.
Magnetic sensor 6 detects magnetic flux of magnets 2 alternately approaching and being removed away, and controller 7 outputs a pulse signal to the electronic circuit of the apparatus. The electronic circuit of the electronic apparatus detects a rotation direction and a rotation angle of actuator 1 based on the pulse signal, and moves the cursor on the displayed menus toward left.
If the operator rotates actuator 1 rightward, forward, backward or in a diagonal direction between them, controller 7 similarly outputs a pulse signal. Namely, the electronic circuit detects a rotation angle and a rotation angle of actuator 1 based on the pulse signal and moves the cursor rightward, upward, downward, or diagonally.
Upon rotating actuator 1 in a desired direction while seeing the display of the electronic apparatus, the operator can move the cursor in the desired direction, selecting menus.
Conventional input device 501, however, detects a rotation angle of actuator 1 just roughly, and causes an error, being prevented from detecting the rotation angle accurately.